Propeller



March 27, 1934.` l Q H HAVlLL 1,952,801

PROPELLBR v Filed Sept. 17. 1930 2 Sheets-Sheet 1 March 27, 1934.

C. H. HAVILL PROPELLER Filed Sept. 1 7, 1930 2 Sheets-Sheet 2 Patented Mar. 1934 PROPELLER Clinton H. Havill, South Orange, N. to Eclipse Aviation Corporation,

J., assigner East Orange,

N. J., a corporation of New Jersey Application September 17,1930, Serial No. 482,586

36 Claims.

This invention `relates to propellers and more particularly to propellers of the type wherein the pitch of the blades may be varied during operation.

It has heretofore been determined that in propeller installations wherein one or more projected blades are employed, there is present, during operation, a marked tendency for the blades to be rotated about their longitudinal axes in f such a manner as to turn the faces thereof into the plane of rotation, that is, the pitch or angularity of the blades will tend to be reduced to zero. This twisting or torsional effect is the result of the action of centrifugal force which tends to reduce the pitch and aero-dynamic force which tends to increase the pitch under certain conditions, the former being of greater magnitude than the latter.

As a result of such above-described torsion, it has been heretofore necessary to employ large and bulky propeller hubs in order to securely maintain the blades at the desired pitchduring A operation, and in the case of variablepitch propellers, it has been necessary to utilize heavy mechanisms having various types of motion multiplying means in order to overcome the eect of torsion to secure an increase in the angularity of the' blades during operation. p

It is accordingly one of the objects of the present inventiorntosprovide a novel propeller so constructed as to obviate the abovementioned disadvantages. l

Another object of the present invention is to provide a propeller embodying novel means for substantially balancing or neutralizing the torsion of the blades.

Another object is to provide novel means util'- izing the thrust of the propeller blades, for changing the angularity of the blades while in operation.

I 'Still another object is to provide in a propeller wherein the pitch of the blades is automatically varied, novel means includingcompound weighted members for substantially counteracting the Y, torsion on the blades.

. A further object is to providein a variable pitch propeller wherein the pitch of the blades 'is varied between predetermined limits, novel means 'including centrifugally-responsive members for predetermining the lower pitch limit, during operation wider varying conditions.

Another object is to provide a propeller where-v in the thrust of the propeller blades is employed in a novel manner for varying thev pitch of the blades andl wherein novel means responsive to centrifugal force is adapted to oppose Wholly or partially the torsion of the blades and to operate to predetermine the speed of rotation of the propeller for a given input power.

A still further object is to provide in a propeller of the above character, a. novel arrangement ofparts in order to secure a compact structure which combineslightness in weight with maximum eiiiciency of operation.

Other objects and novel features of the invention will appear more fully hereinafter from the following detailed description, when taken in connection with the accompanying drawings. It is to be expressly'understood, however, that the drawings are for illustrative purposes only,

-and are not designed as al definition of the limits of the invention, reference being had for this purpose to the appended claims.

In the drawings, `wherein similar reference characters refer to like parts throughout the several views2 Fig. 1 isa horizontal section of embodying the present invention;

Fig. 2 is a'side view, partly in section, of the parts illustrated in Fig. 1;

Fig. 3 is a vsectional end view of the propeller;

a propeller Y and Fig. `4 is a view, partly in section, of a slightly modified form of the invention.

Referring now to the drawings, and more particularly to Figs. 1 and 3 thereof, a propeller embodying the principles of the present invention is illustrated therein as comprising a plurality of projected blades 5 adapted to be carried by a hub member 6 which latter is drivably connected with an extension 'l of a drive shaft, which may be rotatedby any suitable power means, such as for example, a hydrocarbon engine. In order that a large scale drawing may be utilized, a portion only of the blades 5 is illustrated.

In order to .drivably connect the hub 6 with the drive shaft, there is provided an interiorly splined driving block 8 adapted to be received by the splined outer end of the shaft "I, and maintained in proper fixed relation therewith, as by ,means of split front and rear cones 9 and 10 respectively, the bevelled faces thereof being brought into firm engagement with corresponding faces formed on the driving block by means` of a nut member 11 threadedly received by the hereinafter. The hub member 6, as shown, is provided with a pair of axially aligned radially extending hub sockets 14 for receiving the root ends of each of the blades 5.' Each of these' ends is provided with split sleeves 15 secured in position by a clamping ring or collar 16, and the interior surface of each sleeve is so shaped as to provide means for securely gripping the blade root. Such means may be constituted by annular anges or shear shoulders 17 formed on the sleeves 15 which are adapted to engage correspondingly formed shoulders on the root endsof the blades. Preferably, each blade is rotatably mounted in its respective socket, and to this end suitable bearings 18 and 19 are provided, the latter being confined between. an annular' shoulder 20,formed on the sleeve 15, and a mem-- ber 21 threadedly received by the outer end of socket 14. Suitable means for preventing seepage of lubricant from the bearing 19 are provided, and as illustrated, comprise a sealing ring 22 carried by the socket 14, and maintainedin engagement with a nut 23 threaded on the outer end of sleeve 15, by resilient means, such as an expansible spring 24.

Means for rotating the blades in the sockets 14 in order to vary the pitch during operation of the propeller are provided and preferably such means include-the hub and are responsive to the thrust of saidblades to effect the change in angularity in an automatic manner. In the form of the'invention illustrated, such means include an operative connection between the driving block 8 and the blades whereby when the blades and hub move forwardly in response to the thrust force of the blades during rotation of the propeller, the pitch of the blades will be altered.

In order to yieldingly resist the forward movement of the hub, a plurality of suitable resilient members, such as springs 25, are interposed between the hub 6 and a cap member 26, the latter being threadedly received by the outer end of the driving block 8 and locked in position by a nut 27 and washer 28. Preferably, the ends of the resilient members 25 are held in position with respect to member 26 and the hub by means of studs 29 and 30 respectively. In order to permit forward movement of the hub, the member 26 extends outwardly of the hub on either side of sockets 14, Fig. 2, and is provided with cutaway portions 31 laligned with said sockets.

Integrally formed with the cap member 26 is a pair of ears 32 to each of whichv are secured members 33 having apertured bifurcations 34 and 35 between which one end of a link 36 is pivoted in any suitable manner. The other end of the link 36 is pivotally connected to a slotted connecting member orarm 37 which latter extends through an opening 38 formed in hub socket 14 and is secured to the ring 16, sleeve 15 and root end of blade 5 in any suitable manner, such as for example, by threaded connection 39 and pin 40, Fig. 2. Any suitable -protective covering such as an arcuate shaped cap 41 may be provided for the opening 38, and preferably, as shown, such cap is carried by the arm 37 so as to be movable therewith.

By means of the construction above described, it will be apparent that during operation of the propeller, the springs 25 will normally be effective to maintain the hub 6 rearwardly, Fig. 1, the pitch of the blades being then a maximum as indicated by the blade section 5EL shown in dotted lines in Fig. 2. However, when the propeller is in operation and the thrust exerted by the blades is sufficient to overcome the tension of the springs 25, thehub and blade assembly will be moved forwardly relative to the driving block 8, such movement being effective through the link Lesaeor mechanism 36.-37 to rotate the blades in the sleeves'or sockets 14 todecrease the pitch. Referring to Fig. 2, during the forward movement of the hub, the pivotal connection between members 36 and 37 will move inwardly in the direction of` the arrows a and D, the arm 37 moving freely in the opening 38 to secure the variation in pitch of the propeller blades. It is here pointed out that the construction is such that the pitch assumed in response to a particular thrust force will yield maximum propeller efficiency for the conditions imposed.

As heretofore pointed out during operation of a propeller, the force of torsion tendsl to twist the blades into the plane of rotation. as for example, in a clockwise direction, Fig. 2. In the construction shown in this figure, torsion through the component forces indicated by the arrows c and d, tends to respectively move the hub 6 forwardly in opposition to the tension of springs 25a1id to elongate or place the link 36 in tension. 'Ihe result of such forces, unless counteracted in some manner, would be to move the hub forwardly, thereby decreasing the pitch, until the tension of springs 25 balanced the torsion and thrust, or such movement was positively arrested.

In order to substantally balance or neutralize this torsion moment, centrifugally-responsive means are provided which are associated with the operative connections between the driving block and the longitudinally movable hub. .As shown, such means are constituted by an outwardly extending arm 42 formed integrallyv with arm 37, the outer portion 43 of said first-named arm being threaded to receive a weight 44 which may be adjusted to a suitable position along the threaded portion 43 and locked in position by suitable means.

In operation, Fig. 2, the weight- 44 will, due to the effect of centrifugal force, tend to rotate the integrally connected arms 37 and 42 in a counterclockwise direction about the pivotal connection between said arms and the link 36, the result being that a force indicated by the arrow e tending to place the link 36 in compression will substantially offset the force d, and a force indicated at f will substantially balance the force c. Thus by means f the centrifugally-responsive members 44, the torsion may be substantially neutralized. The magnitude of such neutralizing force may be determined by the position and mass of the weight elements. If desired, the effective weight of the counterweight 44 and supporting means therefor, may be increased by enlarging the ring 16 in the region of the threaded connection 39, as indicated at 15a, Figs. 1 and 2.

In certain instances it may be desirable to predetermine the lower pitch angle which the blades are permitted to assume in order to limit the speed of revolution of the propeller. Means are provided for accomplishing this purpose and preferably such means are also responsive tot centrifugal force. As shown, each of the threaded arms 43 is hollow and houses a small weight 45 held in position by resilient means such as a spring 46. Each of these springs is maintained in proper position within the arm by a screw vplug 47. yThe weight 45 and spring 46 are so constituted that during operation, at some predetermined speed, the weight .45 will move outwardly, thus increasing the effective weight of.

the centrifugally-responsive element 44. This will result in a greater torsion neutralizing force and since the force j may under these conditions erence will therefore be had be greater than the force c, due to torsion, the result will be that the hub will move rearwardly until these forces are balanced. This will cause the pitch of the propeller blades to be increased slightly, thus imposing a greater load on the driving engine to decrease the rate of 'revolution thereof.-

A modified form of the invention is disclosed in Fig. 4, this construction being somewhat similar `to that heretofore described with the exception that a gear and rack mechanism is employed for securing the variation in pitch of the blades during thrust-responsive movement of the hub assembly. As shown, the gear and rack mechanism comprises a ring gear 50 secured `adjacent the inner end of the sleeve and which is adapted to cooperate with .a toothed rack 51 carried by the ear 32 of cap 26.

lVIeans are provided for substantially neutralizing the torsion of the blades shown in Fig. 4 and as shown include a bearing race 52, for bearing 19, such race being secured to sleeve 15 in any suitable manner and being provided with a plurality of inclined faces 53. During operation, the outward radial pull of the blade v5, due to centrifugal force, will tend to turn the blade 5 in a direction opposite to that which torsion tends to turn the blade, by reason of the inclined faces 53, and since centrifugal force and torsion are both dependent upon the speed of revolution of the propeller, it is apparent that torsion may be vneutralized at substantially all speeds.

'Ihere is thus provided by the present invenf tion a novel propeller of the variable pitch type wherein the pitch of the blades is secured in a simple and automatic manner. By employing the novel means for neutralizing the torsion of the blades, a lighter and more compact mechanism for changing the pitch may be utilized. Since the pitch of the propeller blades is varied in response to the thrust of the blades, an unusually eicient propeller installation is secured inasmuch as the pitch assumed by the propeller blades under all conditions will be such as to yield maximum propeller eiiiciency. Positiveness in operation is secured by the thrust-responsive means, including the link mechanism 36-37 which renders the construction especially adaptable for aircraft use. By employing the auxiliary counterweight a very eicientfmeans is provided for limiting the rate of revolutions of the propeller in an automatic manner aswell as limiting the minimum bla/des.

While two embodiments of the invention have been illustrated and described, it is to be understood that the invention is not limited thereto but may be embodied in various mechanical forms. For example, the link mechanism 36-37 may be formed other than as illustrated and the counterweight device may also be modified if desired, it being borne in mind, however, that the y same is always responsive to centrifugal force.

`Various other changes may be made in the details of construction and arrangement of parts as well known by those skilled in the art without departing from the spirit of the invention. Refclaiins for a definition of vention. l

What is claimed is: v

1. A propeller having a plurality of blades, means responsive to the thrust ofthe blades to vary the pitch thereof, resilient means for yieldingly resistingoperation of said thrust-responsive the limits of the inpitch condition of the to the appended directly connected to said blades and including centrifugally-responsive masses for neutralizing the torsion onv the blades.

2. A propeller having a plurality of blades, mechanism for automatically varying the pitch of the blades, resilient means for yieldingly resisting operation of said pitch'varying means and means including centrifugally-responsive members carried by said mechanism for opposing the torsional tendency of the blades to assume a zero pitch condition.

3. A propeller having a plurality of blades, means actuated by the thrust of the blades and including a hub for varying the pitch of the blades and means for compensating for the centrifugal moment of the blades said last-named means including -weighted members rigidly connected with said first-named means.

4. In a propeller having a plurality of blades, means responsive to the thrust of the propeller means and means for varying the pitch of the blades, resilient means for yieldingly resisting operation of said thrustresponsive means and means cooperating with said first-named means and carried by the blades to offset the torsional moment of the blades.

5. An aircraft propeller including a plurality of blades, a support for said blades, means for rotating said blades in the support for varying the pitch of the blades, reslient means for yieldingly opposing a decrease in the pitch of said blades, and means pivotally connected with a portion of said first-named means vfor opposing the effect of torsion on the blades.

6. A propeller for aircraft comprising a plurality of blades, means for rotating said blades, means responsive to the thrust of saidl rotating blades and including pivoted members for changing the pitch of said blades, resilient means for yieldingly resisting operation of said thrust-responsive means, and means movable in response to centrifugal force for neutralizing the torsional moment of said rotating blades..`

7. A propeller for aircraft comprising a plurality of blades, means including a hub for rotating said' blades, means responsive to the thrust of said rotating blades and including pivoted members for moving said hub forwardly to. change the pitch of said blades and means movable in response to centrifugal force for balancing the torsion of said blades.

8. In combination, a propeller having a plurality of blades, meansfor varying the pitch of said blades and means for substantially neutralizing the torsion of saidblades said last-named means including a pair of relatively movable centrifugally-responsive elements, one pair for each blade.

9. In combination, a propeller having a plu.- rality of blades, means for rotating said propeller, vmeans for varying the angularity of the blades during such rotation, means for compensating for the torsion of said blades, and means responsive to centrifugal force for increasingthe effect of said torsion compensating means.

y 10. In combination with a rotatable shaft, a hub axially movable with respect to said shaft, a blade carried by the hub and cooperating therewith to move the latter axially in response to the thrust of said blade,` means operable during such axial movement to vary the pitch of said blade and means including relatively movable centrifugally-'responsive `members for compensating for the torsion of the blade. 'y

11.` An aircraft propeller comprising a rotatable shaft, a hub drivably connected therewith', a

isoy

during operation of the propeller,

'plurality of inclined plurality of blades carried by the hub, said hub being axially movable with respect to said shaft in response to the thrust of said blades, pivotally -connected members operatively connecting the blades and shaft to vary the pitch of the blades during movement of the hub relative to the shaft, means for neutralizing the torsion of the blades, and other means responsive to centrifugal force for predetermining the lower pitch angle of the blades.

l2. In a propeller having a plurality of blades, means responsive to the thrust of said blades for automatically varying the pitch of the blades within predetermined limits, centrifugally-responsive means for partially compensating for the torsion of the blades, and other centrifugallyresponsive means for predetermining the lower pitch limit.

13. A propeller for aircraft comprising a plurality of blades, means responsive to the thrust of said blades for varying the pitch thereof said means includingT members connected to each of the blades, resilient means for yieldingly opposing operation of said tl'irust-responsive means, and means comprising counterweights carried by said members for substantially counteracting the torsion of said blades.

14.1n combination, a plurality of propeller blades, means for mounting said blades, means responsive to the thrust of said blades and including Asaid mounting means for altering the angularity of the blades during operation, centrifugally-responsive means for substantially neutralizing the torsion of the blades and means operable at a predetermined speed of rotation' for increasing the effect of said torsion neutralizing means.

15. In combination, a plurality of blades, means for rotating said blades, means responsive to the thrust of said blades for normally changing the pitch thereof, means for neutralizing the torsion of the blades, and other means responsive to a predetermined speed of rotation and cooperating with said thrust-responsive means for limiting the reduction inthe pitch of the blades.

16. A propeller for aircraft comprising a plurality of blades, means for rotating said blades, means responsive to the thrust of said blades,

means responsive to centrifugal force, and means for varying the pitch of the blades said lastnamed means being actuated during normal operation by said thrust-responsive means only and during a predetermined speed' by said thrustresponsive means and said centrifugally-responsive means combined. v

17. Ina propeller having a plurality'of blades, means for rotating said blades, means for automatically varying the pitch of said blades during rotation of the propeller, and other means for substantially neutralizing -the` torsion of the blades said last-named means including a member positioned around each of said blades and having aplurality of inclined faces thereon.

18.' Inapropeller having a plurality of blades, a

` hub for carrying said blades, means drivably connected with the hub for rotating the same, means for automatically varying the pitch of the vblades and other means utilizing the centrifugal force of said blades and including a bearing race having a bearing seats on one face thereof for overcoming the torsion of the blades.

19. A propeller comprising a plurality of blades, a rotatable shaft, a hub, means for drivably connecting said hub and shaft, said `hub being mov- .thrust-responsive movement of the weasel able with respect to said shaft in response to thrust of said blades, and means including mech- `anisms interconnected between said shaft and blades and having a link positioned exteriorly of the hub for rotating the blades about their longitudinal 'axes to vary their pitch during hub.

2C. A propeller comprising a i b, plurality of blades rotatably mounted the means for rotating sad hub and blades, means operable automatically to vary the pitch of the blades, said means including pivoted members intercom nected between said rotating means and blades, said members being connected with said rotating means exteriorly of the hub, resilient means for yieldingly opposing operation of said pitch varying means and means responsive to centrifugal force for partially neutralizing the torsion of the blades.

2l. A propeller comprising a hub, a plurality of blades rotatably carried by said hub, a rotatable shaft, means for drivably connecting said hub and shaft, said hub being longitudinally movable with respect to said shaft, and means operable during such movement to vary the pitch of the blades, said means including a plate rigidly secured to the shaft exteriorly of the hub, a pair of lateral extensions on said plate, and a link mechanism interconnecting the lateral extensions with said blades.

22. A propeller comprising a hub, a plurality of blades rotatably carried by said hub, a rotatable shaft, means for drivably connecting said hub and shaft, said hub being longitudinally movable with respect to said shaft, and means operable during such movement to vary the pitch of the blades, said means including a member rigidly secured to said shaft and positioned exteriorly of the hub, said member being provided with a plurality of outwardly extending arms, and means for pivotally connecting the outer end portions of said arms with said blades.

23. A propeller hub comprising a driving member, a hub member drivably connected thereto, said last-named member being movable longitu- -dinally with respect to said first-named member,

a shaft drivably connected to said driving member, a plurality of propeller blades rotatably mounted in said hub, and means for rotating said blades in the hub during longitudinal movement of the latter relative to the driving member to vary the pitch of said blades, said means in cluding a plate secured to the shaft andpositioned exteriorly of the hub, an arm secured to each blade, and link mechanisms interconnecting said arms with said plate.

24. In a propeller having a hub, a plurality of blades carried thereby, a rotatable shaft drivably connected to the hub, said hub being automatically movable axially of the shaft for varying the pitch of the blades, and means interconnecting said shaft and blades for varying the pitch of the latter during such axial movement of the hub, said means comprising a member secured to each blade and projecting through member secured to the shaft and extending laterally on either side thereof, said last-named member being positioned. exteriorly of the hub, links pivotally connecting said last-named member and said blade members, and means asso- 1` said hub, a

v including a counterweight blades.

26. A propeller comprising a hub, a plurality of blades rotatably mounted therein, a rotatable shaft, means for drivably connecting said hub and shaft, said hub being longitudinally movable with respect to said shaft in response to the thrust of the blades, means interconnecting said shaft and blades for rotating the latter in the hub to vary .the pitch during such longitudinal movement, and means for partially compensating for the torsion of said blades, said means secured to each of said blades interiorly of the hub.

27. A propeller comprising a hub. a shaft for rotating said hub, a plurality of sleeves rotatably with counterweighted portions for partially overi coming the torsion of the blades.

28. A propeller comprising a hub, a plurality of sleeves rotatably carried by said hub, a blade secured within each of said sleeves, a rotatable shaft,means for drivably connecting said hub and shaft, said hub being longitudinally movable,

with respect to said shaft in accordance with the thrust of the blades, a collar encircling each of said sleeves, said collar being provided with a counterweighted portion, and means interconnecting said shaft and said collars adjacent said counterweighted portions for varyingv the pitch of the blades during thrust-responsive movement of the hub. v

29. An aeronautical propeller comprising a rotatable shaft, a hub drivably connected therewith, a plurality of blades rotatably carried by said hub, said hub being axially movable with respect to said shaft in response to the thrust of said blades, resilient means for normally maintaining said hub in such position that the pitch of the blades will be a maximum, said resilient means yieldably opposing thrust-responsive movement of the hub relative to the shaft, mechanism including links operatively connecting said blades and shaft for varying the pitch of the blades during thrust-responsive movement of the hub relative to the shaft, and means for par-v tially compensating for the torsion of said blades which tends to reduce the pitch of the blades, said means including counter-weights associated with the blades interiorly of the hub.

30. An aeronautical propeller comprising a plu-l rality of blades, a rotatable shaft, a hub, means including a member secured to the shaft for drivably connecting the latter with said hub, a plurality of rows of bearings extending longitudinally of said shaft and disposed between said member and the hub for enabling movement of the hub with respect to said member in response to the thrust of the blades during operation of the propeller, means including a plurality of pivotally connected members for varying the pitch of the blades during thrust-responsive movement of the hub, resilient means for yieldably resisting thrust-responsive movement of the hub and tending to normally maintain the latter in such position that the pitch of the blades will be a predetermined maximum, and means including a plurality of counterweights secured to said blades `for partially neutralizing the torsion of the latter.

31. An aeronautical propeller comprising a hub, a plurality of blades rotatably carried by the hub, a rotatable shaft, means including a plurality of rows of bearings aligned with the shaft for drivably connecting the latter and the hub, said hub being longitudinally movable with respect to the shaft in response to the thrust of the blades, means interconnecting said shaft and weights attached to each blade for partially compensating for the torsional tendency of the blades to seek a zero pitch position, and other counterweights positioned exteriorly of the hub and responsive to centrifugal force for limiting the reduction in pitch of the blades during thrust-responsive movement of the hub.

32. An aircraft propeller comprising a rotatable shaft. a hub surrounding said shaft and drivably connected thereto, a plurality of blades rotatably mounted with respect to the hub, and thrust-responsive means for moving said hub rectilinearly on said shaft and including a link mechanism positioned exteriorly of the hub for automatically rotating the blades with respect to the hub for varying the angularity of said blades during such movement of the hub.

33. In an aircraft propeller, a hollow hub, means extending through the hub and drivably connected thereto interiorly of the hub for ro.- tating the latter, a plurality f blades carried by the hub, means responsive to the thrust of said blades while the same are rotating and including a link mechanism secured to said rotating means exteriorly of the hub for automatically rotating the blades about their longitudinal axes for varying the pitch, and resilient means for yieldingly opposing operation of said thrust-responsive means, said resilient means being interposed between said hub and said rotating means.

34. The combination with a rotatable shaft and a hub drivably connected therewith but rectilinearly movable with respect thereto, of a plurality of projected blades carried by said hub, and means operable in response to the thrust of the blades for moving said hub rectilnearly along said shaft and for varying the pitch of the blades during such movement, said means including a pair of members connected together for pivotal movement, at least one of said members being positioned exteriorly of the hub.

35. In a propeller`having a plurality of blades, blade-thrust-responsive means for varying the pitch, land a by each blade for neutralizing the torsion thereon.

36. In a propeller having a plurality of blades, a hub, a shaft drivably connected with said hub, the latter being rectilinearly movable with respect to the shaft in accordance with the thrust ofthe blades, means for varying the pitch of 4the blades during such thrust-responsive movewithin the hub.

CLINTON H. -HAVILL' plurality of counterweights carried 

